1. Field of the Invention
This invention relates to an exercise machine that accurately simulates running, sprinting or jumping movements and can be used as a leg press.
2. Description of Related Art
Both athletes and non-athletes utilize exercise machines to build strength, to prevent injury and/or to improve overall physical condition. There are numerous exercise machines known in the art. Generally, each machine exercises a certain part of the body or a certain set of muscles. Athletes often use exercise machines designed to improve performance of muscles required for their particular sport.
Of particular interest to football players are the muscles used for running, jumping and sprinting. While many exercise machines exercise the leg muscles involved in those maneuvers, no known exercise machine utilizes all of the same muscles in the same manner as those muscles are used in the natural movements of running, jumping and sprinting.
One machine that attempts to simulate running is described in U.S. Pat. No. 3,759,511, issued Sep. 18, 1973 to D. W. Zinkin, et al. While the Zinkin, et al. machine simulates many muscle movements of running, the limited movement of the foot in the foot receiving plates of the Zinkin, et al. make it impossible to simulate the natural movements of running, sprinting or jumping. Additionally, during use of the Zinkin, et al. machine, the torso slides forward on the body support because there is no means for keeping the upper body in a fixed position. This reduces the resistance against which the legs are exercised and reduces the effectiveness of the machine.
There is a need for an exercise machine that closely simulates the natural movements of running, sprinting and jumping. Further, there is a need for such an exercise machine that is flexible so that it may be adjusted to enhance the exercise of specific muscle groups. Finally, there is a need for such an exercise machine to provide a convenient range of resistances so that it may be used not only for conditioning of active athletes but also for rehabilitation of injured athletes.